Midwheel drive wheelchair with independent front and rear suspension

A wheelchair comprising:

• a frame;
• a ground engaging mid-wheel drive wheel connected to the frame;
• a front pivot arm pivotally mounted to the frame at a front pivot point, the front pivot arm having a caster for supporting the frame, the front pivot arm being independent of the drive wheel;
• a rear pivot arm pivotally mounted to the frame at a rear pivot point, the rear pivot arm having a caster for supporting the frame, the rear pivot arm being independent of the drive wheel;
• and
• a linkage connecting the front and rear pivot arms to each other in a manner such that an upward or downward rotation of one of the pivot arms about its pivot point caused by an obstacle encountered during travel on a surface causes rotation of the other pivot arm about its pivot point in an opposite rotational direction.

A wheelchair comprising:

• a frame;
• a front pivot arm pivotally mounted to the frame at a front pivot point, the front pivot arm having a caster for supporting the frame and a second pivot mounting point;
• a rear pivot arm pivotally mounted to the frame at a rear pivot point, the rear pivot arm having a caster for supporting the frame and a second pivot mounting point;
• a ground engaging mid-wheel drive wheel connected to the frame;
• and
• a suspension having a linkage and a resilient member that generates a biasing force onto at least one of the front and rear pivot arms, wherein the front and rear pivot arms are connected together at the front and rear arm second mounting points by a linkage such that an upward or downward rotation of one of the pivot arms about its pivot point caused by an obstacle encountered during travel on a surface causes rotation of the other pivot arm about its pivot point in an opposite rotational direction against the biasing force.

A wheelchair comprising:

• a frame;
• a front pivot arm pivotally mounted to the frame at a front pivot point, the front pivot arm having a caster for supporting the frame;
• a rear pivot arm pivotally mounted to the frame at a rear pivot point, the rear pivot arm having a caster for supporting the frame;
• a ground engaging mid-wheel drive wheel connected to the frame;
• and
• a suspension having a resilient member that generates a biasing force and a linkage connecting the front and rear pivot arms to each other in a manner such that an upward or downward rotation of one of the pivot arms about its pivot point caused by an obstacle encountered during travel on a surface causes rotation of the other pivot arm about its pivot point in an opposite rotational direction, the linkage further transferring the biasing force of the resilient member to both of the pivot arms.

A wheelchair comprising:

• a frame;
• a ground engaging mid-wheel drive wheel connected to the frame;
• a front pivot arm pivotally mounted to the frame at a front pivot point, the front pivot arm having a caster for supporting the frame, the front pivot arm being independent of the drive wheel;
• a rear pivot arm pivotally mounted to the frame at a rear pivot point, the rear pivot arm having a caster for supporting the frame, the rear pivot arm being independent of the drive wheel;
• and
• a linkage connecting the front and rear pivot arms to each other, and a resilient member connected to any one of the front pivot arm, the rear pivot arm, and the linkage, the resilient member generating a biasing force that is applied to urge the pivot arms to a neutral position, and the linkage is configured in a manner such that an upward or downward rotation of one of the pivot arms about its pivot point caused by an obstacle encountered during travel on a surface causes rotation of the other pivot arm about its pivot point in an opposite rotational direction, the linkage further transferring the biasing force of the resilient member to both of the pivot arms.

A wheelchair comprising:

• a frame;
• a front pivot arm pivotally mounted to the frame at a front pivot point, the front pivot arm having a caster for supporting the frame at a proximal end and a linkage pivot mount at a distal end;
• a rear pivot arm pivotally mounted to the frame at a rear pivot point, the rear pivot arm having a caster for supporting the frame at a proximal end and a linkage pivot mount at a distal end;
• a ground engaging mid-wheel drive wheel connected to the frame;
• and
• a linkage connecting the front and rear pivot arms to each other at the front and rear linkage pivot point mounts in a manner such that an upward or downward rotation initiated by one of the pivot arms about its pivot point caused by an obstacle encountered during travel on a surface causes rotation of the other pivot arm about its pivot point in an opposite rotational direction.